Mounting of a rotatable chisel in mining machinery

Abstract

A chisel arrangement for mining machines includes a rotatable chisel including a working part, a supporting flange arranged adjacent to the working part, and a shaft arranged adjacent the supporting flange, the shaft having a lug and an end flange at an and opposite from the supporting flange. A chisel holder is arranged around apportion of the shaft, and a friction ring is arranged around the lug and at least partially against the chisel holder. The end flange of the shaft, a portion of the lug and a portion of the friction ring are arranged exterior of the chisel holder.

What is claimed is:  
     
       1. A rotating chisel assembly for insertion in a chisel holder, comprising: 
       a shaft and a working part with a flange, which acts as a support at a front of the chisel holder, when the shaft of the rotating chisel is inserted in an accommodating hole of the chisel holder;  
       the shaft having a lug provided with an end flange and an upper chamfer connecting to an upper shaft part of the shaft, and a lower chamfer connecting the end flange; and  
       a friction ring disposed over the lug and having upper and lower slopes adapted to the upper and lower chamfers of the lug.  
     
     
       2. The rotating chisel assembly of  claim 1 , further comprising a recess formed in a transition from the upper chamfer of the lug to the upper shaft part and a groove formed in a transition from the lower chamfer of the lug to the end flange. 
     
     
       3. The rotating chisel assembly of  claim 1 , wherein a transition from the upper chamfer of the lug to the upper shaft part forms an undercut. 
     
     
       4. The rotating chisel assembly of  claim 3 , wherein the undercut is bounded by a an annular inner inclined surface defining an acute angle with respect to a peripheral surface of the upper shaft part. 
     
     
       5. The rotating chisel assembly of  claim 4 , wherein the friction ring concludes with upper and lower end edges at ends of the upper and lower slopes, wherein the upper and lower end edges are chamfered. 
     
     
       6. The rotating chisel assembly of  claim 5 , wherein the chamfer of the upper end edge of the upper slope of the friction ring is matched to the inner inclined surface of the undercut in the transition between the lug and the upper shaft part. 
     
     
       7. The rotating chisel assembly of  claim 5 , wherein a diameter of the lug is smaller by twice a thickness of the friction ring than a diameter of the upper shaft part. 
     
     
       8. The rotating chisel assembly of  claim 1 , wherein a diameter of the lug is smaller than a diameter of the upper shaft part. 
     
     
       9. The rotating chisel assembly of  claim 1 , wherein the upper and lower chamfers are inclined at an angle of 10° to 35° respectively with respect to a virtual cylindrical peripheral surface extending upward and downward from a cylindrical surface of the lug between the upper and lower chamfers. 
     
     
       10. The rotating chisel assembly of  claim 1 , wherein a diameter of the lug is smaller than a diameter of the end flange. 
     
     
       11. The rotating chisel assembly of  claim 1 , wherein an axial end surface of the end flange has a recess. 
     
     
       12. The rotating chisel assembly of  claim 1  in combination with the chisel holder, wherein the end flange at the shaft of the rotating chisel protrudes out of the accommodating hole of the chisel holder when the rotating chisel is inserted in the chisel holder. 
     
     
       13. The rotating chisel assembly of  claim 1 , wherein the friction ring is a substantially tubular body having a slot in a longitudinal direction forming two mutually opposite friction ring edges. 
     
     
       14. The rotating chisel assembly of  claim 13 , wherein the friction ring edges have opposing recesses. 
     
     
       15. The rotating chisel assembly of  claim 13 , wherein the friction ring has a surface between the upper and the lower slopes and transitions between the surface and the upper and lower slopes are rounded. 
     
     
       16. A chisel arrangement for mining machines, comprising: 
       a rotatable chisel including a working part, a supporting flange arranged adjacent said working part, and a shaft arranged adjacent said supporting flange, said shaft having a lug and an end flange at an end opposite from said supporting flange;  
       a chisel holder arranged around a portion of said shaft; and  
       a friction ring arranged around said lug and at least partially against said chisel holder;  
       said end flange of said shaft, a portion of said lug and a portion of said friction ring being arranged exterior of said chisel holder.  
     
     
       17. The arrangement of  claim 16 , wherein said shaft has substantially the same diameter as an inner diameter of said chisel holder, said friction ring having a thickness, said lug having a diameter smaller than a diameter of said shaft to accommodate twice the thickness of said friction ring between said lug and said chisel holder. 
     
     
       18. The arrangement of  claim 16 , wherein said shaft has a niche formed on a first side of said lug more proximate said supporting flange and a groove formed on a second side of said lug more proximate said end flange. 
     
     
       19. The arrangement of  claim 18 , wherein said shaft further includes a chamfer arranged between said lug and said niche, said shaft including an inwardly directed surface such that said niche is defined by said chamfer and said inwardly directed surface. 
     
     
       20. The arrangement of  claim 18 , wherein said shaft further includes a chamfer arranged between said lug and said groove, said end flange having an inner surface such that said groove is defined by said chamfer and said inner surface of said end flange. 
     
     
       21. The arrangement of  claim 18 , wherein said shaft further includes a first chamfer arranged between said lug and said niche, said shaft including an inwardly directed surface such that said niche is defined by said first chamfer and said inwardly directed surface, and a second chamfer arranged between said lug and said groove, said end flange having an inner surface such that said groove is defined by said second chamfer and said inner surface of said end flange, said first and second chamfers being oriented at the same angle relative to said lug. 
     
     
       22. The arrangement of  claim 21 , wherein said friction ring has end edges and a chamfer adjacent each of said end edge, one of said chamfers of said friction ring being arranged to extend into said niche and the other of said chamfers of said friction ring being arranged to extend into said groove to thereby restrain movement of said friction ring over said lug, said chamfers of said friction ring being inclined relative to a friction surface of said friction ring at the same angle as said chamfers of said shaft are oriented relative to said lug. 
     
     
       23. The arrangement of  claim 18 , wherein said friction ring has end edges and a chamfer adjacent each of said end edge, one of said chamfers being arranged to extend into said niche and the other of said chamfers being arranged to extend into said groove to thereby restrain movement of said friction ring over said lug. 
     
     
       24. The arrangement of  claim 16 , wherein said lug has a diameter smaller than a diameter of said end flange. 
     
     
       25. The arrangement of  claim 16 , wherein said end flange has a diameter smaller than a diameter of said shaft. 
     
     
       26. The arrangement of  claim 16 , wherein said end flange has a front end having an inwardly directed recess. 
     
     
       27. The arrangement of  claim 16 , wherein said friction ring includes end edges, a middle portion having a peripherally extending friction surface and chamfers arranged between said middle portion and said end edges. 
     
     
       28. The arrangement of  claim 27 , wherein said chamfers are inclined at an angle of from 10° to 35° to said friction surface. 
     
     
       29. The arrangement of  claim 27 , wherein each of said end edges is inclined at an angle of from 0° to 20° relative to a respective plane defined by a tip of said end edge. 
     
     
       30. The arrangement of  claim 27 , wherein said friction ring includes a gap defined by gap edges, each of said gap edges including a recess. 
     
     
       31. The arrangement of  claim 27 , wherein said friction ring includes said chamfers having curved chamfers adjoining said middle portion, said curved chamfers a same radius of curvature as one another.